Field of the Invention
The present invention relates to an information processing apparatus, a method of controlling the same, and a storage medium, and more particularly to a technique for controlling a response of an information processing apparatus capable of connecting to a network in a power saving state, to a communication request.
Description of the Related Art
In recent years, along with spreading of network environments, such as wireless LANs (local area networks), devices have become popular which are equipped with a wireless LAN function enabling wireless connection to a network via a wireless LAN access point provided on the network. For example, in an office in which a wireless LAN is constructed, data is exchanged by wireless communication between a multifunction peripheral (multifunction printer) equipped with the wireless LAN function and a plurality of PCs (personal computers).
Further, with increasing awareness of environmental problems, there is a strong demand for introducing a power saving technique for reducing power consumed by every electrical equipment used e.g. in an office. As the power saving technique for wireless LAN-equipped devices, IEEE 802.11v is standardized by IEEE (Institute of Electrical and Electronic Engineers). Functions constituting the IEEE 802.11v standard include proxy ARP (address resolution protocol). In proxy ARP, a wireless LAN access point responds to an ARP request on behalf of a wireless LAN client device thereunder. This makes it possible to prevent the wireless LAN client device from operating only for responding to broadcast ARP requests frequently received via the network, whereby the wireless LAN client device can continue the power saving state.
On the other hand, as a power saving technique for a multifunction peripheral, a technique is known which reduces standby power consumption by automatically shifting the multifunction peripheral to the power saving state in a case where the apparatus in a normal state is not operated for a predetermined time period.
Further, there has been proposed a technique in which a sub control unit smaller in size than a main control unit is provided for operation by minimum power supply in the power saving state, and network processing to be performed by the main control unit when in the normal state is caused to be performed by the sub control unit on behalf of the main control unit when in the power saving state, to thereby realize both of network connectivity and power saving.
The network processing performed by the sub control unit when in the power saving state is smaller in scale than the network processing performed by the main control unit, and it is difficult for the sub control unit to respond to all communication requests from PCs to the multifunction peripheral. The sub control unit determines whether or not it is possible to process a received communication request, and if it is impossible to process the request, the multifunction peripheral needs to be quickly shifted from the power saving state to the normal state, to cause the main control unit to respond to the communication request via the network. To realize this, there has been disclosed a technique for determining whether an information processing apparatus in the power saving state can respond to a communication request received in the power saving state, or the information processing apparatus is required to shift to the normal state to respond to the communication request. For example, in Japanese Patent Laid-Open Publication No. 2010-288225, there has been proposed a technique for performing pattern-based discrimination between communication requests received by an information processing apparatus in the power saving state.
In the technique disclosed in Japanese Patent Laid-Open Publication No. 2010-288225, the information processing apparatus is equipped with a function for determining whether the packet pattern of a received communication request is a proxy response pattern for executing proxy response in the power saving state or a proxy response candidate pattern different from the proxy response pattern, and if the pattern of the communication request is not a proxy response pattern, the information processing apparatus shifts from the power saving state to the normal state. Further, information for the above-described determination is updated according to a condition of reception of the communication request. As a consequence, the information processing apparatus realizes switching between the response processing in the normal state and that in the power saving state. Further, by setting patterns of communication requests frequently received as proxy response patterns, the frequency of occasions of response in the power saving state is increased whereby it is possible to maintain the power saving state for a longer time period.
Here, suppose that an information processing apparatus equipped with the wireless LAN function performs wireless connection to a network via a wireless LAN access point supporting proxy ARP defined by the IEEE 802.11v standard. Under such a network environment, the wireless LAN access point can respond to an ARP request addressed to the information processing apparatus on its behalf. The information processing apparatus does not receive the ARP request, and hence it is not necessary to provide a pattern setting for responding to the ARP request in the power saving state.
However, if the technique disclosed in Japanese Patent Laid-Open Publication No. 2010-288225 is applied to the information processing apparatus under the above-mentioned network environment, the following problem arises: The information processing apparatus does not receive the ARP request since it is connected to the network via the wireless LAN access point supporting proxy ARP defined by the IEEE 802.11v standard, and for example, a packet pattern associated with an ARP request, which has been initially set as a proxy response pattern, becomes useless due to zero frequency of usage. Further, this prevents other patterns of packets which are frequently received from being set as proxy response patterns, which makes it impossible to keep the power saving state longer than otherwise. Furthermore, load of processing for transfer of packet patterns and a memory capacity required for holding the packet patterns are wastefully increased by the useless pattern. In short, the information processing apparatus connected to the wireless LAN access point is required to set proper packet patterns which are not useless, according to a result of determination of whether or not the access point performs proxy ARP.